* Over 6 trillion cubic feet of gas may be produced
* Company agreed to use pollution fighting technologies (Adds agreement details, drilling area)
WASHINGTON, June 9 Anadarko Petroleum Corp's plan to develop a huge natural gas field in Utah cleared a key hurdle by reaching an air-quality agreement with the federal government, the Interior Department said on Thursday.
The project by Anadarko's (APC.N) Kerr-McGee unit in the Greater Natural Buttes Area involves drilling up to 3,675 new gas wells to produce more than 6 trillion cubic feet of gas over 10 years.
The project was proposed in 2006 but has been delayed in the past over air quality concerns.
In the first two months of this year ozone pollution exceeded acceptable levels in the area where the new wells would be drilled, the Interior Department said.
Five of those days were considered "very unhealthy" for people in the area.
Working with the Interior Department and the Environmental Protection Agency, Anadarko agreed to several air pollution control technologies, including a pilot project to evaluate using natural gas fueled drilling rigs to mitigate emissions.
Parts of Utah sometimes have some of the highest winter time ozone levels in the country, due to a sharp increase in drilling, according to the department.
"We must be especially vigilant that such projects proceed in the right manner and with the right mitigation," said Bob Abbey, director of the department's Bureau of Land Management.
The air quality agreement will be part of the project's a draft environmental impact statement that will be published in the Federal Register on Friday and open for public comment for 45 days. A final decision on the project is expected later this year, a BLM spokesman said.
The Anadarko project would cover 8,147 acres, which is about 5 percent of the 162,911 acres in the Greater Natural Buttes' existing gas producing area in the state's Uintah County. (Reporting by Tom Doggett; Editing by Dale Hudson and Sofina Mirza-Reid)